Electric switch



0ct. 28, 1952 H. c. SWAN 56,005

ELECTRIC swgTcH Filed nec. 15, 195o 2 SHEETS-SHEET 1 H. C. SWAN ELECTRICSWITCH Oct. 28, 1952 Filed Dec. 15, 195o 2 SHEETS-SHEET 2 Patented Oct'.28, 1952 UNITED STATES PATENT QFFICE' ELECTRIC SWITCH Y ApplicationDecemherr1'5, 1950, Serial,No. 200,976

8 Claims;r

This invention relates to an electric switch-operative to control twolelectrical circuits inaccordance with the current ow therethrough.

It is amongV the objects of the presentV invention to provide athermoelectric switch having all of the characteristics of the switchdisclosed-in the patent to Werner, No. 2,242,769, issued May 20,1941,but differing in construction, resulting in a much smaller switch whichpermits it to be mounted within the frame of the electric motor it isadapted to control, thereby eliminating the addition of undesirablehousing provisions Ywhich destroy the symmetry of the motorand ruin itsappearance.

Reducing the size of the switch not only substantially reduces its costof manufacture, butv ing drawings Whereina preferred embodiment of thepresent invention isclearly shown.

In the drawings:

Fig. 1 is a plan view of the switch shown in full contact makingposition.

Fig. 2 is a view similar to Fig. l, showing the switch in a position inwhich one ofits circuits is broken and the other maintained.

Fig. 3 is a similar View of the switchshowing both of its circuitsbroken.

Fig. 4 is an end View of the switch.

Fig. 5 is a perspective view of the switch sans the insulating platewhich carries the stationary contacts and upon which the switch ismounted.

Fig. 6 is a side view of the switch looking in the direction of arrow 6of Fig. 4.

The plate upon which the switch is mounted maiT be of any suitableinsulating material and for purposes of illustration, the present switchis shown made of a transparent synthetic-insulating compound throughwhich the switch mechanism maybe viewed. This insulating base has twostationary contacts 2| and 22 mounted thereupon in any suitable mannerand in'proper relative positions one to the other. The switch mechanismconsists of a rigid frame 23, U-shaped for a portion of its length,which portion consists of the top web portion 24 and two depending sideportions 25 and 2li having ears 2l and 28 respectively which extendthrough the insulatingv base 20 and are twistedso asto rigidly lockthe:-

frame-to the-base-20. Frame23has Vtwo angular-- substantially atVright:-

projections 30 and 3| angles to -the web portion 24 thereof. The angularprojection 3%- of` the rigid-frame 231hastwo-` ilexiblecontact'blades-32 and' 33 secured thereto with a spring 34 sandwichedtherebetween. These. superposed elements 32, 34 and 33 are anchored.

to the projection 30" by meansA of a rivetl 35;-

Blade spring-32 at its free-end, or more particu-- larlythe end thereofoppositeits anchored tend;

has a contact element 37| attached thereto whichi is adapted tocooperate withthe-stationary contact 2| to make-and'break afcircuit.Likewise;

trallyslotted portions in the two contac-tcarrying flexible blades 32and33. The Fig. 5clearlyillustrates `the slot 4| in the-exible blade-33,this slot 4| being identical toslot 42-inthe-exible blade 32 asshownFig.v 5. The abutment Mlissecured to spring 34 bymeans of a projection43 on the abutment which-extends through an opening-in the spring-34vandis rivetedoverI the: spring. It willbe noted thatthe abutment 40` ismounted edgewise upon spring 34' and-is substantially at right anglesthereto so that said] abutment moves transversely or edgewisefthroughtheslotted iiexible contactv carryingblades-32 'and 33.; The one end of theabutmentjdil'; more particularly the endthereofadjacentfto its pointof,4

anchor to spring-34, has one-endjof the thermoelectric` elementl 5|)Hsecured thereto -so` as yto be in electrical connectiontherewith. Theotherv end of this thermoelectric element is secured to anadjustable-.member l5| insulatingly--supportedLA upon the frameprojection 3| by an insulating coil 52. Normally the-spring 34urges-the-abutrnent 40 in a counterclockwise direction'asregards Fig.-l, movement ofthe-abutment- 49 bythe springhowever being opposed bythe-thermoelee-tric ele-- ment Eil-which tends-to movetheabutment inythe: opposite direction under certain A conditions,

butunderiother conditions,- will permit movementA of the abutment bythespringdL-ina-counter-- clockwise direction as regards Figs. 1,`2and-3.

The abutmentmemb'er 491 has two contiguous saw-toothshapednotches 55 and56 in its end edge oppositethe edge-or portion toiwhichtheV This"thermoelectric-v element is attached.

notch end edge of the abutment 4E) moves through the slotted contactcarrying exible blades 32 and 33 in a plane at right angles to the planesurface of said blades. The iiexble blade 32 has a resilient linger t!!provided thereon, this nger being shown integral with blade 32 andextending therefrom at a point in close proximity to the contact 3lthereon. The finger 6i! is of such a length that When its free end isseated in the saw tooth notch 5t of the abutment member li, said fingertil is biased to exert a pushing force upon the Contact carryingflexible plate 32. Likewise plate 33 is provided with a resilient fingeriii extending therefrom and secured thereto in the vicinity of theContact 38 thereon, this finger El being likewise biased When its freeend is seated in the saw tooth notch 55 'of the abutment lle, the lingerbeing operative to exert a pushing force upon the flexible contactcarrying blade 33. The knife edges of the saw tooth notches 55 and 5tare, as has been said before, contiguous, being spaced a predetermineddistance one from the other. When the position of the abutment il@ is asillustrated in Fig. l, notches 55 and 5t are on the side of therespective ilexible blades 33 and 32 so that the fingers 6l and 66 arebiased to exert a pushing force upon the blades 33 and 32 respectivelyto cause their respective contacts 33 and 3l electrically to engage therespective stationary contacts 22 and 2 i. Under these circumstances,the thermoelectric element 5s is comparatively cool and thus expandedand in its initially tensioned condition. However, if current is causedto flow through the thermoeiectric element 5t, which is in circuitconnection with the contacts 3l and 38 through the abutment lli! and therespective engaging fingers E@ and @i of the blades then, upon a pre- Ydetermined current flow through the thermoelectric element 5t, saidelement will become heated, causing it to expand, its expansionpermitting the spring Sii to become effective to move the abutment d@counterclockwise as regards Fig. 1. In response to such counterclockwisemovement of the abutment ll, thenger engaged end of the saw tooth notch55 in said abutment will be moved toward alignment with the flexiblecontact carrying blade 32 and when said notch and its engaged linger @ilreaches a predetermined position on the lower side of the blade 32 asshown in Fig. 2, the motivating force of the biased finger @il will bereversed thereby causing it quickly to thrust the blade 32 and itscontact 3l toward the stop end 65 of the frame 23 which projects fromthe portion or side 25 thereof, whereby the circuit formerly passingbetween the contacts 3l and 2i will be broken. If expansion of thethermoelectric element 58 continues, due to continued or predeterminedincrease in current flow therethrough, spring 34 will continue to movethe abutment lil counterclockwise as regards Fig. l, thereby moving thesaw tooth notch 55 of the abutment and its engaging end of the finger 6lto the side of the contact carrying ilexible blade 33 in which thepushing force of the finger is reversed whereby blade 33 and its contact3S will be moved away from stationary contact 22 to break the circuit.In moving in this direction, the rigid extension @t on the blade 33,normally not in engagement with flexible blade 32, will be moved toengage and rest against said blade 32 as shown in the Fig. 3. The Fig. 2indicates the position of the switch mechanism in which the contact 3lhas been moved out of engagement with its stationary contact 2i While 4contact 38 is still in circuit completing engagement with its stationarycontact 22.

From the aforegoing, it will be seen that in response to a predeterminedcurrent flow through the thermoelectric element its expansion iseffected, thus permitting the blade spring 3ft to become active toactuate the abutment member i0 in a counterclockwise Vdirection asregards Figs. l, 2 and 3. During the predetermined range of suchcounterclockwise movement by the abutment liti, linger @El of thecontact carrying flexible blade 32 is adjusted and brought into relativeposition with the blade 32 so that said linger will thrust the blade andits contact 3l into circuit breaking position as shown in Fig. 2.Continued expansion of the thermoelectric element 53 results in anadjustment of the abutment iii counterclockvrise to bring finger iiiinto a position relative to the main body portion of the flexiblecontact carrying blade 33 so that finger El will also thrust its contactcarrying blade 33 to move contact 33 out of engagement with contact 22and the extension t5 of blade 33 into engagement with flexible blade 32as shown in Fig. 3.

Thus, it may be seen that contacts 3l and 3S are successively moved outof engagement with their respective stationary contacts 2l and 22 andtheir respective circuits broken in response to and in accordance withthe expansion of the thermoelectric element 5S, due to predeterminedcurrent flows therethrough.

When the thermo-electric element 5S is permitted to cool due to areduction or complete discontinuance of current flow therethrough, itwill contract and consequently actuate the abutment it in opposition tothe effort of spring 3e counterclockwise, thus moving said abutment ilclockwise as regards the Figs. 1, 2 and 3. After the abutment d@ ismoved clockwise from its position as shown in Fig. 3, the saw toothnotch E5 and its engaging resilient finger Sil will first be moved tothe opposite side of the contact carrying flexible blade S2, thustending to effect a movement of said blade 32 toward the stationarycontact Zi. However, in this instance, blade 32 engaged by the rigidextension 6G on blade 33, will be retarded in its movement toward thestationary contact 2l due to the resisting force of the blade 33 whichis still being urged into the open position as shown in Fig. 3 by itsre- Silient linger Si. However, as the abutment 4B continues to moveclockwise under the effect of the spring 3e, being gradually released bythe thermo-electric element iid, the notch 55 and its engaging nger iiiwill be moved toward alignment with the contact carrying flexible blade33. As the notch engaging end of finger iii approaches blade 33 from itsposition in Fig. 3, nger 6i will gradually exert a weakening force uponblade S3 to urge it into the position as shown in Fig. 3 and when thenow opposing forces of iingers dei and t reach a balance at apredetermined position of the abutment ri, moving clockwise, bothfingers and ti will concurrently and with a snap action thrust theirrespective contact carrying 'blades 32 and 33 toward the stationarycontacts so that the contacts 3l and 38 on said blades respectivelywillelectrically engage their respective stationary contacts 2i and 22 asshown in Fig. l. Thus it will be seen that the rigid extension @t on thecontact carrying flexible blade 33 will, when properly adjusted, effectsimultaneous engagement of the contacts 3i and S8 with their respectivestationary contacts under the effect of the spring fingers E0 and 6lbeing slowly adjusted clockwise by the abutment member All, activated bythe spring 34.

It will be seen that the present construction differs from theconstruction disclosed in the above identined Werner Patent No.2,242,769 in that the contact carrying flexible blades in this instanceare mounted upon the rigid frame and not upon the hinged or movableabutment irame as shown in the patent. The abutment in the presentinstance mounted upon a blade spring attached to the rigid frame isindependently movable relatively to the contact carrying blade springs.These differences in construction provide a switch having the samecharacteristics as the patented switch but permitting the switch to bemade more compact and smaller than would be possible to build thepatened switch. The Figs. l, 2 and 3 illustrate the switch at slightlylarger than double size while the Werner patent illustrates a switch ofthe same characteristics at full size. It may readily be seen that theswitch of the present invention, due to its construction, would reduireconsiderable lesser material and therefore would be cheaper to produceand at the same time, by requiring less material, provides an importantfactor under conditions when material supplies for commercial use arebeing curtailed and restricted.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

l. An electric switch comprising in combination, a rigid frame; amovable abutment; exible means securing the abutment to the rigid frame,said flexible means constantly urging the abutment in one direction;thermo-electric means attached to both the rigid frame and the abutmentand operative to actuate the abutment in the opposite direction inopposition to said ilexible means; stationary contacts; cooperatingilexible contacts secured to the rigid frame; and a flexible biasingelement on each exible contact, said biasing elements respectivelyseating in contiguous notches in the abutment, each biasing elementbeing operative to actuate its respective flexible contact in onedirection or the other, dependent upon the position of the notchoccupied by it, relatively to the respective flexible contact,

2. An electric switch comprising in combination, a rigid frame; amovable abutment; a blade spring anchored to the abutment; stationarycontacts; cooperating flexible contacts; common means securing the bladespring and flexible contacts to the rigid frame, said blade springconstantly urging the abutment in one direction; thermo-electric meanssecured between the rigid frame and abutment and being operative toactuate said abutment in the opposite direction in opposition to theblade spring; contiguous notches in the abutment; and a ilexible biasingnger on each flexible contact, each finger being seated in a respectivenotch in the abutment, said fingers being operative to move theirrespective flexible contacts in one direction or the other in responseto movement of their respectively engaged abutment notches to the sideof the flexible contact opposite its resultant movement.

3. An electric switch comprising in combination, a rigid frame; a bladespring and two ilexible contacts anchored to the rigid frame; an

abutment securedfto and carriedby saidv blade v spring which constantlyurges the abutmentiin one direction; stationary contacts each adapted tobe engaged by a respective flexible contact;

a thermo-electric element insulatingly secured to the rigid frame andelectrically anchored to the abutment, said element being operative toactuate the abutment in the opposite direction in'opposition to theblade spring; and a resilient finger on each flexible contact, oneend'of each'" finger being secured to its respective ilexiblevcon tact,theother end of each-finger being seated*- upon the edge of the abutmentand therebl` biased, one finger contiguous to the other and in`vv suchpositions relatively to their respectivefflexia ble contacts as toprovide over-center-"mechaenism adjusted by the movementof theabutment;' to thrust said flexible contacts in one direction or theother` relatively to the-stationary conta-cts.

4; An electric switch comprisingin combina"-Y tion, a rigid frame havingan angular extension;

two stationary contacts; two longitudinally slotted, resilient contactblades each engageable with a respective stationary contact and anchored at one end to the angular extension of the frame; a blade springanchored with the resilient contact blades to the frame; an abut# mentsecured to the blade spring which urges the abutment to move in onedirection through" the slots of the resilient contact blades,transversely thereof, said abutment having two con-v tiguous notches inits outer end edge; a thermoelectric element electrically anchored tothe abutment and insulatingly to the frame, said element being operativeto operatethe abutment in opposition to the blade spring wherebythe-notches in the actuator are moved across the transverse plane of theresilient blades in one direction or the other; and resilient fingers oneach resilient contact blade, biased by seating the free ends thereof ina respective notch of the abutment, said lingers thrusting theirrespective contact blades in one direction or the other dependent uponto which side of the resilient contact the notches are moved by eitherthe blade spring or thermo-electric element.

5. An electric switch comprising in combination a rigid frame; twostationary contacts; two flexible contacts each adapted to engage astationary contact, each flexible contact being longitudinally aperturedfor a portion of its length; a resilient blade; common means anchoringone end of each llexible contact and the blade to the frame, the bladebeing sandwiched between the flexible contacts; an abutment anchored tothe blade which constantly urges the abutment in one directiontransversely of the two flexible contacts, said abutment having twocontiguous notches in its one end edge; a thermo-electric elementelectrically secured to the other end of the abutment and insulatinglyanchored to the frame, said element being operative to exert anactuating force upon the abutment in opposition to the blade springwhereby the abutment notches are shifted transversely of the respectiveflexible contacts from one side to the other thereof; a resilient fingeron each exible contact, each finger being biased by seating the free endthereof in a notch of the abutment whereby actuation of the abutmentbythe thermo-electric element or the blade spring causes said flexiblecontacts simultaneously to engage or successively to disengage theirstationary contacts respectively.

G. A device in accordance with claim 5 in which, however, an adjustableextension is proaeiaoot vided on the one ilexible contact, saidextension only engaging the other flexible contact when both contactsare disengaged from their respective stationary contacts, wherebyconcurrent engagement of the flexible and stationary contacts isfacilitated in response to actuation of the abutment by thethermo-electric element.

7. An electric switch comprising in combination. a rigid frame;stationary contacts; cooperating flexible contacts one end of each beinganchored to the frame; a blade spring secured to the frame; an abutmentcarried by the blade spring which constantly urges the abutment in onedirection transversely of the flexible contacts, said abutment havingcontiguous notches in its free end edge movable from one side to theother of the transverse plane of a respective flexible contact;thermo-electric means insulatingly secured to the frame and electricallyto the abutment, said means being operative to move the abutment inopposition to the blade spring; resilient fingers on each flexiblecontact, each linger being biased by seating one end in a respectiveabutment notch, each finger being operative to actuate its respectiveflexible contact in accordance with the position of the notch itoccupies, relatively to its ilexible contact; and an adjustable rigidprojection on one flexible contact, operative to engage the otherflexible contact only when both flexible'contacts are disengaged fromtheir respective stationary contacts.

8. An electric switch comprising a base, two insulated, stationarycontacts carried by the base; a rigid frame secured to the base; twoslotted, liexible blades, one end of each blade being anchored to theframe, the other end of each blade supporting a contact one of whichcooperates with one stationary, the other with the other stationarycontact for controlling electric circuits; a blade spring anchored tothe frame in superposed relation to the flexible contacts; an abutmentcarried by the blade spring, said abutment having two contiguous notchesin its outer end edge the abutment being movable transversely of theflexible blades through the slots thereof; a resilient finger secured toeach cf said iiexible blades adjacent the respective contacts thereoneach finger being biased by placing its free end into pivotal engagementwith a respective notch in the abutment, the bias of each fingereffecting operation of the contact carrying blades toward or away fromtheir respective cooperative stationary contacts in accordance with theposition of the notches in the abutment relatively to the respectivecontact carrying blades; and a thermo-electric element insulatinglyconnected to the rigid frame and electrically to the abutment, saidelement being operative in accordance with current now therethrougheither to actuate said abutment against the effect of its supportingblade spring to cause contact disengagement or to permit said blade tomove the abutment to effect contact engagement.

HARRY C. SWAN.

REFERENCES CITED The following references are of record in the le ofthis patent:

UNITED STATES PATENTS Number Name Date 2,242,769 Werner May 20, 19412,278,990 Hall Apr. 7, 1942

